JP2000028665A - Device and method for analyzing electromagnetic field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify input operation by utilizing CAD data for drawing. SOLUTION: CAD data for drawing which are created in a step S1 are stored in a step S2 and are converted into information on a lattice. Thickness information and material quality information are added to the lattice in a step S3, and information is given to elements according to the position and material quality of each lattice in a step S4, thus finishing the input operation of an analysis model. An analysis calculation is made in a step S5, and a calculation result is outputted in a step S6. Since CAD data for drawing are utilized, input operation can be simplified drastically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic field analyzing apparatus and an electromagnetic field analyzing method for analyzing an electromagnetic field of an electronic apparatus, an antenna or the like in a time domain.

[0002]

2. Description of the Related Art Conventionally, techniques for electromagnetic field analysis include a technique in a frequency domain and a technique in a time domain.
In general, when a plurality of substances having different medium constants are included or in a complicated shape, an electromagnetic field analysis in a frequency domain such as a moment method is employed. However, in the analysis in the frequency domain, calculation cannot be performed unless a large approximation is used, and there has been a problem that the more complicated the model, the more difficult it is to perform an accurate analysis.

On the other hand, the analysis technique in the time domain, which has not received much attention because of the shortage of the computing capacity and the storage capacity of the computer, has recently been improved in the computing capacity and the storage area of computers such as personal computers and workstations. This has been made possible by increasing the capacity of the system, and many analysis examples have been published.

[0004] In the analysis method in the time domain, a Maxwell equation, which is a basic equation of an electromagnetic field, is converted into a difference equation on the time axis, and the discrete equation is discretized on a grid network in the space domain so as to satisfy the Maxwell equation. The calculated electric and magnetic fields are obtained by successively calculating the above difference equations. This method has an advantage that the shape of the object to be analyzed and the medium constant constituting the object can be arbitrarily selected. FIG. 14 shows the characteristics of the analysis method in the frequency domain and the time domain.
Shown in

An analysis method based on an analysis theory on a time axis includes an FD-TD (Finite Differ).
ence-time domain) method, TLM (Tr
announcement-Line Modeling)
And the spatial network method. For example, FD-
The TD method is based on a difference between Maxwell's equations in time and space, and calculates the electromagnetic field alternately.
The og algorithm calculates each electromagnetic field variable of the analysis system at each time step.

In this analysis method, the analysis target is generally three-dimensional, and the analysis region including the analysis target (model) is usually divided by a rectangular grid as shown in FIGS. In general, the interior 1 of the lattice has dielectric constant, magnetic permeability,
Conductivity information is assigned. Here, the shape of the lattice need not necessarily be a cube. Basically, the electric field 2 (black circles) is assigned along each side of the grid, and the magnetic field 3 (white circles) is assigned in the direction normal to the center of the plane. The dielectric constant and conductivity are finally given by the average of the numerical values given to each electric field, as shown in FIG. 16, and the magnetic permeability is given to the grid in contact with each magnetic field, as shown in FIG. It is finally given by the average of the given numbers.

The distance between each electric field point and each electromagnetic field point is
Δx, Δy, and Δz in the x, y, and z axis directions, respectively. That is, it is necessary to input data representing the analysis target in three dimensions.

Incidentally, the accuracy of the calculation result using such a grid network depends on the fineness of the grid of the grid network, and the finer the mesh, the higher the accuracy. For an analyte having a relatively complex structure, the required number of grids increases. In such a case, the amount of data to be input to the computer is extremely large, and if the input operation is to be performed manually,
It takes a long time due to the large number of steps.

Therefore, in order to improve the efficiency of data input work, in addition to calculation software, three-dimensional structure input software for performing electromagnetic field analysis using a computer such as a personal computer or a workstation has been developed.

However, in order to make full use of such three-dimensional structure input software, knowledge of an electromagnetic field and learning of how to use the software are required, so that only limited engineers can use the software. It is not possible, and it takes a long time to learn how to use it. Even if this software is used, considerable man-hours are still required to input a model from scratch.

Therefore, a CAD (Computer) for drafting, which is widely used for drafting, not for electromagnetic field analysis, is generally used.
It is possible to use an Aided Design device. By making it possible to create an analysis model directly from CAD data created by a CAD device for drafting,
It is possible to streamline data input work.

[0012] Methods corresponding to the analysis method on the frequency axis, such as the moment method and the finite element method, have already been developed. In such a conventional electromagnetic field analyzer, the data for analysis is obtained by converting CAD data created by a CAD device for drafting.

The CAD data for drafting is converted into a known conversion method for data exchange between different CAD systems, for example, DXF (Drawing Exchange Fo).
rmat), IGES (Initial Graphi)
c Exchange Specification)
Many formats use such formats.

Next, the features of the DXF will be briefly described. D
There is no concept of unit in XF, but millimeter [m
m] or inch [inch] notation. Also, there is no idea of a scale, and all data are actual. The figure is created on an image layer or layer (LAYER). Regardless of the drawing on any of the layers, a combined figure can be obtained as a whole drawing. Layers are fixed by number, some of which cannot be named by the user, and some of which can be named independently. By controlling the display and non-display of each layer, it is also possible to display only the target graphic.

Due to these characteristics, DXF is a multi-layer printed circuit board, LSI (Large-Scale Integrated Circuit).
(gration) chips, coplanar antennas, and the like.

FIG. 18 is an explanatory view showing a state in which a multilayer printed circuit board inside an electronic device is drawn by a CAD device for drawing. FIGS. 18A to 18C show the drawing data of the image layers 11 to 13, respectively, corresponding to the respective layers of the multilayer substrate. A wiring 15 is drawn on the image layer 11, a ground plate (ground) 16 is drawn on the image layer 12, and a wiring 17 is drawn on the image layer 13.

As described above, in general CAD data, data is represented by line segments. In the moment method, which is an analysis method in the frequency domain, data can be input using only line segments. Therefore, it was easy to obtain the data for analysis by using the CAD data. It should be noted that the models that can be analyzed are naturally limited to those that can be expressed only by line segments.

However, when creating an analysis model for electromagnetic field analysis on the time axis, not only data of a line segment but also three types of data including a solid and a plane are required.
For this reason, conventionally, it has not been possible to obtain analysis data in the time domain by using two-dimensional CAD data for drafting.

When modeling an object to be analyzed such as a multilayer printed circuit board, an LSI chip, and a coplanar antenna, it is necessary to model not only wiring but also a ground plane (ground). FIG. 19 is an explanatory diagram showing a state where such a wiring or a ground plane is drawn. FIG. 19A shows the drawing data, FIG. 19B shows the central part by a diagonal line, and FIG. 19C shows that the peripheral part is a ground plane by the diagonal line.

The CAD for drafting only performs drawing by line segments. For this reason, it is not possible to judge whether the image indicates a surface or a three-dimensional object based on the drawn image.
There is no information on the material. Therefore, in order to extract the part surrounded by the line, that is, the part having the surface shape,
An inside / outside determination is made.

As an example of the conventional inside / outside determination method, there is a virtual difference mesh method disclosed in Japanese Patent Application Laid-Open No. 9-185729. For each mesh of the virtual difference mesh data, draw a half-line in an arbitrary direction from the representative point (for example, the center of gravity), check the number of intersections with the shape element such as the cross-sectional line of the outermost point, and check whether the inside or outside is even or odd Determine.

However, FIG. 19A shows whether the wiring 22 is drawn on the image layer as shown by the diagonal lines in FIG. 19B or whether the wiring 22 is drawn as shown by the diagonal lines in FIG. Ground plate 23 on layer
Cannot be determined whether or not is rendered. That is,
Even if the above-described method of judging inside / outside is adopted, in the case of FIG. 19B, since there is no shape outside, no intersection point occurs and it is difficult to use the outside as a judgment criterion.

Therefore, in the example of FIG. 19A, it is not possible to specify which portion the planar portion is. For this reason, it was not possible to obtain analysis data in the time domain by using the two-dimensional CAD data for drafting.

Further, as described above, the accuracy of the calculation result of the electromagnetic field analysis on the time axis is affected by the fineness of the mesh of the grid network, and the finer the mesh, the higher the accuracy. However, there is no problem if the storage capacity of the computer performing the analysis is infinite, but it is actually finite. Therefore, the number of grids that fall within the range of the storage capacity of each computer, that is, the analysis area is determined by the size of the analysis model and the desired frequency, so that the size of the grid that divides the analysis model is limited.

Therefore, in particular, in the electromagnetic field analysis on the time axis using a cubic or rectangular parallelepiped grid, a part of the model finer than the grid disappears, or a groove or a hole is filled to make the determination difficult. There is also a possibility that it will. In this case, even if the electromagnetic field simulation is performed, the result is different from the actual CAD data for drafting, and the meaning of the simulation itself is lost. As described above, it is not possible to obtain analysis data by using arbitrary CAD data for drafting.

The FD of the analysis method on the time axis
Since the TD method, the TLM method, the spatial network method, and the like have a common basic principle, it is considered that the above-mentioned problems are common to all the methods.

[0027]

As described above, in the above-described conventional electromagnetic field analyzing apparatus, if the analysis technique in the time domain is adopted, CAD data for drafting cannot be diverted. However, there was a problem that it was extremely complicated and difficult.

According to the present invention, since the CAD data for drafting can be used, the data input operation can be simplified, and the modeling peculiar to the electromagnetic analysis in the time domain can be facilitated. It is an object to provide an electromagnetic field analysis device and an electromagnetic field analysis method.

[0029]

An electromagnetic field analysis apparatus according to a first aspect of the present invention provides a plurality of CAD data consisting of line information based on the shape of an analysis model. Conversion means for converting into information corresponding to the grid, data addition means for adding material information to each grid obtained by the conversion means, based on information on the position and material in the analysis area of each grid hand,
Using a discretization unit that adds information to the elements of each of the lattices, and each lattice to which information is added by the discretization unit,
The electromagnetic field analysis apparatus according to claim 5 of the present invention further comprises: an analysis unit configured to perform an electromagnetic field analysis in a time domain of the analysis model. A visualization unit that visualizes each grid to which information is added to an element by the conversion unit, and a correction unit that can correct information to be added to an element of each lattice. The electromagnetic field analysis device according to claim 5, wherein the correction value storage unit that stores the information corrected by the correction unit, and the information that is stored in the correction value storage unit is obtained from line information. The present invention comprises an inverse conversion means for converting the data into CAD data, and a CAD data correction means for correcting a corresponding portion of the CAD data based on the output of the inverse conversion means. An electromagnetic field analysis method according to the thirteenth aspect, comprising: converting CAD data consisting of line information based on the shape of an analysis model, converting the CAD data into information corresponding to a plurality of grids that partition a predetermined analysis region; Data addition processing for adding material information to each grid obtained by the conversion processing, and discretization for adding information to each grid element based on information on the position and material of each grid in the analysis area. And an analysis process of performing an electromagnetic field analysis in the time domain of the analysis model using each grid to which information is added by the discretization unit.

According to the first aspect of the present invention, the CAD data is converted into information corresponding to a grid by a conversion means. Material information is added to this grid by data adding means. The discretizing means assigns information to each grid element based on the information on the position and the material of the grid in the analysis area. This completes the input operation for creating the analysis model, and the analysis means performs an electromagnetic field analysis on the analysis model in the time domain.

In claim 5 of the present invention, each grid to which information has been added by the discretization means is visualized by the visualization means. The correction means corrects information given to the elements of the grid. By referring to the visualization means, it is easy to correct the information to be assigned to each grid element.

According to a seventh aspect of the present invention, when the input operation for creating the analysis model is completed by the processing of the discretization means and the information given to the element is corrected by the correction means, the correction value is corrected. It is stored in the value storage means. The inverse conversion means converts the contents stored in the correction value storage means into CAD data. Using this conversion result, the CAD data correcting means corrects the original CAD data.

According to a thirteenth aspect of the present invention, the CAD data is converted into information corresponding to the grid by the conversion process, and the material information is added to the grid by the data addition process. Thereby, the CAD data can be used for creating an analysis model. After discretization processing gives information to the elements of each grid based on information on the position and material of the grid in the analysis area, electromagnetic field analysis in the time domain of the analysis model is performed by the analysis processing.

[0034]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the electromagnetic field analyzing apparatus according to the present invention.

In FIG. 1, the input unit 31 is constituted by a keyboard, a mouse, or the like, and supplies a signal based on a user operation to the control unit 32. The control unit 32 controls the whole of the apparatus. The storage unit 33 stores software necessary for the operation of the present apparatus and other data from inside and outside. The display 34 is C
It is configured by an RT or the like, and is controlled by the control unit 32 to perform screen display.

Next, the operation of the embodiment configured as described above will be described with reference to the flowchart of FIG. It should be noted that the flowchart of FIG.
This is realized by executing software stored in.

First, at step S1 in FIG. 2, drafting data is created. The analysis model is drawn using a drafting CAD device (not shown). Now, as an analysis model, a multilayer printed circuit board, an LSI (Large-Scale)
(Integration) A model is assumed in which a number of planes parallel to the xy plane, such as a chip, overlap in layers (hereinafter referred to as 2.5 dimensions). For example, it is assumed that drawing is performed using a multilayer wiring board as an analysis model as shown in FIG. In this case, as shown in FIGS. 18A to 18C, the layers are divided, the wiring 15 is drawn on the layer 11, the ground plate 16 is drawn on the layer 12, and the layer 13 is drawn on the layer 13. Draws the wiring 16. The drawing C
When drawing is performed by AD, the length of each line segment is determined with the cell size as the minimum unit in consideration of the cell size described later. Basically, different materials are drawn by dividing the image layer.

The CAD data created in this way is converted into a known conversion method for data exchange between different CAD systems, for example, a CAD for drafting by DXF, IGES, or the like.
After being converted into data, it is stored in the storage unit 33 via an input / output device (not shown) (step S2).

As described above, the CAD data for drafting does not have material information, and the figure is composed of only line information. Thus, in the present embodiment, the thickness between layers, material information, and the like are added. In step S3, such data addition is performed.

First, the size of each cell is specified in order to discretize the region including the analysis model into a lattice (cell) network. The CAD data for drafting is data indicating the planar shape of the analysis model. By determining the cell size in the x and y directions, the analysis model given by the CAD data for drafting can be divided into cells on a plane. it can.

Further, the size of the cell in the z direction is also determined. Next, data in the z direction is input for each image layer. That is, the thickness and material of the substrate, the presence / absence of wiring, and the material thereof are input for each cell in the z direction. Thus, the shape in the thickness direction is added to the plane shape given by the CAD data for drafting, and the material of the plane shape given by the CAD data for drafting is specified. These shapes (sizes)
The material and the like are specified in, for example, a rectangular parallelepiped cell unit.

Next, in step S4, discretization into a lattice network is performed. First, let the grid network (analysis area) be x,
The number of cells used in the y and z directions is used to determine where to place the analysis model in the grid network (analysis area). Next, data based on the position and the material in the area is input for each cell. That is, in the discretization, a three-dimensional grid network is virtually arranged on the CAD data for drafting, and the position of each grid point is checked in which position of the region composed of a plurality of components, This is performed by inputting the value of the medium constant of the region as an argument of the region into an array having the positions of the lattice points as arguments.

There are the following two ways of defining the medium constant. In other words, there are a method of assigning constants to the three sides of the grid and a method of assigning one constant to the entire grid. In these two methods, the former is used for discretizing a linear or planar area, and the latter is used for discretizing a block-shaped area.

For example, information for specifying the material is assigned to each lattice, and information such as dielectric constant, magnetic permeability, and conductivity is assigned to sides and surfaces of each lattice.

The same medium constant is given the same number or name. The number or name of each side component and the medium constant are both stored as data in the storage unit 33. The number or name of each side component may be stored in the storage unit 33 in association with the medium constant of the component.

The input of the analysis model is completed by the processing up to step S4.

In general, at the time of designing a printed wiring board or the like, design using a CAD for drafting is performed, and the CAD for drafting created here is diverted to data input work for electromagnetic field analysis. Data entry work is significantly reduced.
In particular, in the case of a printed wiring board or the like, the number of parts is large and the shape of each part is complicated, and the number of steps required for input is significantly reduced as compared with the case where input work is performed by CAD for electromagnetic field analysis.

Next, an analysis calculation is performed in step S5. Since a general method can be employed for the analysis calculation in step S5, a description of a specific method for obtaining an electromagnetic field at a grid point on the grid network will be omitted. Thus, the electromagnetic field is calculated on the time axis, and desired analysis results such as the electromagnetic field intensity, S parameter, and radiation pattern are obtained (step S6).

As described above, in the present embodiment, CAD data created by a CAD device for drafting is used,
By adding information in the thickness direction together with the material to the planar shape obtained from the CAD data, discretization into a lattice network can be performed by a relatively simple operation. In other words, instead of creating a new model for electromagnetic field analysis, a model capable of electromagnetic field analysis in the time domain is created by reading and discretizing CAD data for drafting already created for another application. Thus, the analysis model can be easily modeled in a very short time.

FIG. 2 shows an example in which a two-dimensional drawing CAD apparatus is used, but a three-dimensional drawing CAD apparatus is used.
When the apparatus is used, information on the material may be input at the time of discretization processing to a lattice network as data addition processing.

FIG. 3 is a flowchart showing an electromagnetic field analysis method according to another embodiment of the present invention. In FIG. 3, the same procedures as those in FIG. This embodiment can be realized by the apparatus shown in FIG. 1, and the only difference is the program stored in the storage unit 33. 3 is realized by the control unit 32 executing software described in the storage unit 33.

The processing up to the discretization into the lattice network in step S4 is the same as that in FIG. In this embodiment, after discretization into a grid network, display processing is performed in step S7, and the display result is good (OK) or bad (N
G). That is, the control unit
The display unit 32 creates display data based on the input data of the analysis model and supplies the display data to the display unit 34. This allows the operator to display on the display screen (not shown) of the display unit 34
The display of the analysis model and the analysis region can be seen.

As described above, in the FD-TD method, the analysis region including the analysis target is usually divided by a rectangular parallelepiped grid as shown in FIGS. Information on dielectric constant, magnetic permeability, and electrical conductivity is assigned inside the lattice.

FIG. 4 is an explanatory diagram for explaining the assignment of information to the grid.

As described above, the information to be assigned to the grid includes information to be assigned to each side (line element) of x, y, and z and information indicating the material of the grid. In order to indicate the material of the grid, for example, the control unit 32 displays the entire surface of the grid 41 with a predetermined color corresponding to the material. Also the grid
If data is assigned to all four sides surrounding each surface 41, a diagonal line 43 is applied to a surface 42 surrounded by these four sides. In the case where the fact that data is assigned to each side is displayed alone, the color of each side 44 is set to a predetermined color different from the other sides. With such display, the material, dielectric constant, magnetic permeability, conductivity, and the like of each lattice can be displayed.

The operator checks the display on the display unit 34 to determine whether or not there is any correction. As confirmation items, whether the analysis model is divided at least without disappearing,
The calculation area is sufficient. As a result of the discretization, when these conditions are satisfied, a slight correction such as addition of a feeding point is performed while confirming on the display unit 34 (step S8).
).

If the condition is not satisfied, the process returns from step S7 to step S3, and data is added again. Thereafter, steps S3 to S7 are repeated to add data until the condition is satisfied.

Thus, in the present embodiment, the input of the analysis model is completed by the processing up to step S8.

Subsequent processing is the same as the flow of FIG.

FIG. 5 is a flowchart for explaining another embodiment of the present invention. In FIG. 5, the same steps as those in FIG. This embodiment can be realized by the apparatus shown in FIG. 1, and the only difference is the program stored in the storage unit 33. The flow of FIG. 5 is realized by the control unit 32 executing software described in the storage unit 33.

In the discretization process to the lattice network in step S4, the components of the sides in the three directions of the rectangular parallelepiped lattice and the medium constants represented by the entire lattice are manually input by the input unit 31 for each analysis. In the present embodiment, this input operation is automated.

By the data addition processing in step S3,
The material for each grid in the analysis area is determined, and the position of each grid in the analysis area is also determined by the discretization processing to the grid network in step S4. Therefore, at this point, the information given to each grid is necessarily determined. The elements used for each grid are determined to some extent, and it is possible to configure an element table as side constituent elements and volume medium data.

When the data adding process is completed and the position of each grid is designated, the control unit 32 reads out the data corresponding to these pieces of information from the element table and sets it in each grid in step S9 of FIG. I do.

The reading from the element table and the writing to the element table can be performed during the processing of steps S3, S4 and S7. In addition, by storing the side components and the volume medium data, which are the contents of the element table, in a text file, not only the processing by the control unit 32 but also the element table can be easily corrected by an editor or the like in another microcomputer system. It is possible.

As described above, in the present embodiment, the input operation is automated using the element table, and the operation for creating the analysis model can be significantly simplified.

Further, by using the element table,
It is easy to change the elements given to each grid. For example, FIG.
As shown in FIG. 4, in the electromagnetic field analysis in the time domain, the analysis including the nonlinear element can be performed. That is, the electrical characteristics of the side indicating the nonlinear element are obtained by transient analysis or measurement, and this is formulated as a function of time and stored in the element table. Thereby, there is also an advantage that a temporal change in the analysis result can be easily grasped. Note that the characteristics of the nonlinear element may be calculated by an electric circuit simulator.

FIG. 6 is a flowchart showing an electromagnetic field analysis method according to another embodiment of the present invention. 6, the same steps as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. This embodiment can be realized by the apparatus shown in FIG. 1, and the only difference is the program stored in the storage unit 33. The flow in FIG. 6 is realized by the control unit 32 executing software described in the storage unit 33.

The present embodiment uses a drafting CA based on an analysis model modified according to the results of electromagnetic field analysis.
The D data is modified.

After the correction processing in step S8 is performed, the data is converted into analysis data in step S11 and stored in the storage unit 33. In step S12,
The analysis data is converted into CAD data for drafting.

FIG. 7 and FIG.
FIG. 4 is an explanatory diagram for explaining conversion into AD data.

First, as shown in FIG. 7, the positions of the wiring diagrams 51 and 52 and the ground plane diagram 53 are designated from the analysis data. That is, a surface to be replaced with two dimensions is specified. Next, the discretized model is assembled and converted into line information of CAD data for drafting. FIG. 8 shows analysis data on the x, y plane of a 3 × 2 lattice. Medium information (black circles) is assigned to the x and y sides of each lattice. The boundary of the same material can be determined based on the medium information. For example, it is assumed that the medium information is represented by (x, y) values representing the sides of each lattice.

Assuming that only the six lattices in FIG. 8 are made of the same material, medium information indicated by black circles in the x direction is (1, 1), (2, 1), (3, 1), (1). , 3),
(2, 3), (3, 3), and in the y direction, medium information indicated by black circles is (1, 1), (1,
2), (4, 1), and (4, 2). From the data of these analysis models, the end point is (1,
Line segment data indicating rectangles 1), (1, 3), (4, 1), and (4, 3) can be obtained.

The CAD data thus obtained is:
In the next step S13, comparison is made with the original CAD data for drafting. With respect to the original CAD data for drafting, it is determined whether or not the CAD data obtained in step S12 has a defect such as partial disappearance or filling of holes. If there is a defect (NG), the CAD data obtained in step S12 is corrected using a drafting CAD device in step S14, and then the corrected CAD data is corrected in step S2.
Save the data. Then, the processing from step S3 to step S12 is repeated again.

If there is no problem (OK), the process shifts from step S13 to the next step S5 to perform an analysis calculation. In the next step S15, it is determined whether the calculation result is good (OK) or bad (NG). If defective, the process returns to step S8 to make a correction, and the process from step S12 is repeated. If good,
In step S16, as the final modified model, step S16
The CAD data for drafting obtained in step 12 is determined, and the process ends.

As described above, in the present embodiment, it is possible to not only create an analysis model using the CAD data for drafting, but also to reflect the correction at the time of creating the analysis model on the CAD data. As a result, the burden of designing a multilayer printed wiring board or the like can be significantly reduced.

FIG. 9 is a flowchart showing an inside / outside determination method employed in an electromagnetic field analysis method according to another embodiment of the present invention.

In the present embodiment, in the drawing data creating process in step S1 in FIG. 2, a rectangle is drawn in advance, thereby making it possible to make a reliable inside / outside determination. Step S21 is a procedure for performing such a rectangular drawing process. That is, a rectangle is drawn so as to surround the graphic in addition to the graphic originally required. For example, when performing an electromagnetic field analysis of a circuit board, a rectangle representing the board itself is drawn on a figure of a component on the circuit board. The drawing of this rectangle can be easily changed whether or not it is used for the inside / outside judgment by drawing on a predetermined image layer on which an originally required figure is not displayed.

The next step S22 is a process of reading graphic data including the rectangle drawn in step S21. The next step S23 is a process for setting a plurality of reference points in a portion outside the rectangle drawn in step S21. A half line is drawn from the reference point, and if the number of intersections with the figure representing the analysis model is even, it is determined to be inside, and if it is odd, it is determined to be outside.

Step S25 is processing for storing a reference point when it is determined to be outside, and step S26 is processing for storing a reference point when it is determined to be inside. The next step S27 is a process of determining whether or not the inside / outside determination using each reference point is the same. If they match, the process ends. If they do not match, the process returns to step S23 to set a new reference point and repeat the inside / outside determination.

Next, the operation of the embodiment configured as described above will be described with reference to the explanatory diagram of FIG.

As the analysis model, a 2.5-dimensional model such as a multilayer printed circuit board is assumed. FIG. 10 shows a state in which a predetermined layer of such a multilayer printed board is drawn by a CAD device for drafting. The wiring 64 is drawn on the image layer 66. In step S21, a rectangle 61 is drawn on another image layer 67 so as to surround the drawing portion of the wiring 64. That is, the rectangle 61 may be considered to represent the substrate itself.

Next, in step S22, the CAD data of the wiring 64 including the rectangle 61 is read, and a plurality of reference points 62 are set outside the rectangle 61 in step S23. next,
A half line is drawn from the reference point 62, and the inside / outside judgment is made from the number of intersections of the half line and the drawn line (step S24).

As shown in FIG. 10, the number of intersections 65 is even. In this case, in this case, in step S26, the reference point is stored so that the wiring 64 indicates the inside. Similarly, for the other reference points, it is determined whether the number of intersections is an even number or an odd number.

When the judgment is made for all the reference points,
In the next step S27, it is determined whether or not the determination results at all the reference points match. If they match, the process is terminated. Otherwise, the reference point is shifted and the inside / outside judgment is performed again. For example, when there are N reference points, each reference point is shifted by θ≪360 / N [°] with the center position of the analysis model as an axis, and repeated until the determination results of the N reference points match. .

As described above, in the present embodiment, when it is impossible to judge whether the inside or outside is determined only by the inside / outside judgment, the inside / outside judgment can be made by drawing a rectangle indicating the outside. It is. That is, the range of the inside / outside determination is limited, and it is easy to reverse the inside / outside determination.

FIG. 11 is a flowchart showing a drafting data creation process used in the electromagnetic field analysis method according to another embodiment of the present invention.

The present embodiment is for reducing an error generated in the discretization processing of the analysis model.

Step S31 is a unit selection process. In the unit selection process, a drawing unit is set to start drawing. As the drawing unit, a notation such as millimeter [mm] or inch [inch] may be selected. In the next step S32, a drawing range is designated. In this process, the range in which the analysis model can be designed in the actual size is set as the drawing range. Note that the drawing range is set with a margin as compared with the figure.

In the present embodiment, the next step S
At 33, the size of the snap and grid is specified. The grid is a pattern of points spread over an area designated as a drawing range, and can be used for positioning and displaying distances. The snap limits the movement of the cursor. By setting the snap, the cursor moves at a defined interval. That is,
Since points cannot be specified at intervals other than the intervals specified by snaps, accurate specification is possible even when the operator moves the cursor with a mouse or the like to specify points. Therefore, by using both at the same time, CAD
It is possible to prevent an error from occurring at the time of discretization using the model created in.

In the present embodiment, by setting the units of the grid and the snap in accordance with the size of the grid, it is possible to prevent an error from occurring at the time of discretization.

Next, an image layer is set. In the case of a multi-layer, drawing is performed in each layer, but dimension lines for drafting are also drawn in another layer. Further, even in the same layer, those having different materials are drawn in different layers. In this case, a rectangle surrounding the model is drawn on one of the layers (step S3).
Four).

Next, in step S35, the plane shape of the analysis model is drawn. Next, in step S36, it is determined whether or not the grid division is performed satisfactorily (OK) (NG). That is, when the created CAD data for drafting is discretized into a lattice network in step S4 in FIG. 2, it is determined whether or not division into a lattice is appropriate.

FIG. 13 is an explanatory diagram for explaining the determination of the validity of the grid division.

FIG. 13 shows a drawing example of a coplanar line. The track 72 is drawn on the display showing the main plate 73.
A gap 71 is provided between the track 72 and the ground plane 73. The main plate 73, the track 72, and the gap 71 are indicated by broken lines 75 to 78.

A gap 71 is defined by the line segments 75 and 76 and the line segments 77 and 78. Now, it is assumed that the grid at the time of discretization is a grid 74 shown by a square in FIG. In this case, the division by the lattice 74 is not appropriate. That is, the lattice 74
Includes the track 72, the gap 71, and the ground plane 73,
74 cannot be given appropriate information. Therefore, in this case, it is determined in step S36 that the division is not appropriate, and the processing shifts to modeling in step S35. In this way, the correction of the CAD data for drafting is repeated until it is determined that a proper division is performed.

In the case of FIG. 13, the size of the grating 74 may be made sufficiently small so that the grating 74 does not extend over the line segments 77 and 78. Then, it is determined in step S36 that the division is appropriate, and the process ends.

As described above, in the present embodiment, it is possible to optimize the model division before the discretization of the analysis model, and as a result, it is possible to realize the modeling without the discretization error due to the grid size. can do.

Note that, for example, the lengths of the sides of the grid in the three directions of x, y, and z in 2.5 and three dimensions do not need to be equal, and the grid shape may be a rectangular parallelepiped. Therefore, step S
In 33, when the size of the snap and the grid is set to divide the analysis model into a grid, the size may be different for each direction. That is, it is apparent that the accuracy of the divided analysis model can be further improved by changing the length of the side of the lattice in each of the three directions.

FIG. 12 is a flowchart showing a drafting data creation process employed in the electromagnetic field analysis method according to another embodiment of the present invention.

This embodiment is for preventing an error from occurring in the discretization processing of the analysis model.

In step S35, a plane shape of the analysis model is drawn. The processing before step S35 may be the same as that in FIG. In the next step S37, an important part is designated.

That is, in step S37, a portion considered to be important when dividing into grids, for example, a fine portion, is designated, and this portion is drawn so as to be displayed differently from other portions. For example, for an important part, a line type, line width, color, or the like different from other parts is used. Note that the line types include solid lines, dotted lines, broken lines, and chain lines. Obviously, these line types, line widths, colors, and the like may be properly used depending on the importance.

For example, the display shown in FIG. 13 is performed. FIG.
In the coplanar line shown in (1), the gap 71 between the line 72 and the ground plane 73 is important. As shown in FIG.
If the width of the gap 71 is smaller than one side of
And the ground plate 73 are connected, and the gap 71 disappears in this portion.

Therefore, as shown in FIG. 13, the gap 71 is drawn using broken lines 75 to 78, and the other portions are drawn using solid lines. For example, for the portion drawn by the broken line, the validity of the division is determined by displaying the evaluation result by a display, a buzzer, or the like at the time of determining the validity of the division in the next step S36 so that the validity can be reliably determined. Can be.

As described above, in the present embodiment, by designating an important portion, it is possible to easily recognize a point to be noted when judging the validity of division.

The present invention is not limited to the above embodiments, but can be variously modified. For example, in the above embodiment, the analysis target is 2.5 dimensions, but it is possible to correspond to 3 dimensions or the like, and the shape and format of the analysis model are not particularly limited.

[0107]

As described above, according to the present invention, it is possible to divert CAD data for drafting, thereby simplifying the data input operation, and at the same time, peculiar to the electromagnetic analysis in the time domain. This has the effect that modeling can be facilitated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an electromagnetic field analysis apparatus according to the present invention.

FIG. 2 is a flowchart showing an embodiment of an electromagnetic field analysis method according to the present invention.

FIG. 3 is a flowchart showing another embodiment of the present invention.

FIG. 4 is an explanatory diagram for explaining assignment of information to grid elements.

FIG. 5 is a flowchart showing another embodiment of the present invention.

FIG. 6 is a flowchart showing another embodiment of the present invention.

FIG. 7 is an explanatory diagram for describing the embodiment in FIG. 6;

FIG. 8 is an explanatory diagram for describing the embodiment in FIG. 6;

FIG. 9 is a flowchart showing another embodiment of the present invention.

FIG. 10 is an explanatory diagram for explaining the embodiment in FIG. 9;

FIG. 11 is a flowchart showing another embodiment of the present invention.

FIG. 12 is a flowchart showing another embodiment of the present invention.

FIG. 13 is an explanatory diagram for explaining the embodiment in FIGS. 11 and 12;

FIG. 14 is a table showing characteristics of electromagnetic field analysis in a frequency domain and a time domain.

FIG. 15 is an explanatory diagram for explaining a lattice in a time domain.

FIG. 16 is an explanatory diagram for explaining a lattice in a time domain.

FIG. 17 is an explanatory diagram for explaining a lattice in a time domain.

FIG. 18 is an explanatory diagram showing a state in which a multilayer printed circuit board inside an electronic device is drawn by a CAD device for drafting.

FIG. 19 is an explanatory diagram showing a state where a wiring or a ground plane is drawn.

[Explanation of symbols]

S1 ... drafting data creation processing, S2 ... CAD data storage processing, S3 ... data addition processing, S4 ... discretization processing to a grid network, S5 ... analysis calculation processing

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Manabu Kuwahara 1st address, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa F-term in the Toshiba R & D Center 5B046 AA07 BA06 CA00 FA00 JA07

Claims (13)

[Claims] 1. A conversion means for converting CAD data consisting of line information based on the shape of an analysis model into information corresponding to a plurality of grids defining a predetermined analysis area; Data addition means for adding material information to each of the grids obtained, and discretization means for adding information to elements of each of the grids based on information on the position and material of each of the grids in the analysis region, An electromagnetic field analysis apparatus comprising: an analysis unit that performs an electromagnetic field analysis in the time domain of the analysis model using each grid to which information is added by the discretization unit. 2. The method according to claim 1, wherein the CAD data is two-dimensional information, and wherein the data adding unit adds thickness information and material information to each grid obtained by the conversion unit. The electromagnetic field analysis device according to claim 1. 3. The electromagnetic field analyzer according to claim 1, wherein the CAD data is obtained by drawing the shape of the analysis model on a different layer for each material. 4. The discretizing means has an element table for information to be given to elements of each of the grids, and refers to the element table based on information on a position and a material of each of the grids in the analysis area. 2. The method according to claim 1, further comprising: automatically assigning information to elements of each of the lattices.
An electromagnetic field analysis apparatus according to claim 1. 5. The electromagnetic field analyzing apparatus according to claim 1, wherein the visualization means visualizes each grid to which information has been added to the element by the discretization means, and the information provided to the element of each grid can be modified. An electromagnetic field analyzing apparatus, comprising: a correction unit configured to: 6. The visualization means displays each grid by a line segment, and presents information given to an element by a color of each line segment, a color of a plane surrounded by the line segment, a pattern, or a combination thereof. The electromagnetic field analysis apparatus according to claim 5, wherein: 7. The electromagnetic field analysis apparatus according to claim 5, wherein a correction value storage means for storing information corrected by said correction means, and a CAD comprising information stored in said correction value storage means as line information. An electromagnetic field analysis apparatus comprising: an inverse conversion unit that converts data into data; and a CAD data correction unit that corrects a corresponding portion of the CAD data based on an output of the inverse conversion unit. 8. The method according to claim 1, wherein the CAD data includes rectangular line information surrounding the shape of the analysis model.
8. The electromagnetic field analysis apparatus according to any one of 5 or 7. 9. The method according to claim 1, wherein the CAD data is constituted by line information in units of a length based on the size of the grid. Electromagnetic field analyzer. 10. The CAD data according to claim 1, wherein the CAD data is configured by line information based on a line type, a line width, a color, or a combination thereof based on characteristics of the analysis model. An electromagnetic field analysis apparatus according to any one of the preceding claims. 11. A system comprising: a presentation unit for presenting to an operator that line information based on the shape of the analysis model is line information based on a specific line type, line width, color, or a combination thereof. Item 11. An electromagnetic field analysis device according to item 10. 12. The method according to claim 1, wherein the CAD data is optimized so as not to have a line segment finer than the size of the grid before the processing by the discretization means. 8. The electromagnetic field analysis apparatus according to any one of 5 or 7. 13. A conversion process for converting CAD data consisting of line information based on the shape of an analysis model into information corresponding to a plurality of grids that partition a predetermined analysis region; A data addition process of adding material information to each of the grids obtained, and a discretization process of adding information to the elements of each of the grids based on information on a position and a material in the analysis region of each of the grids, An electromagnetic field analysis method comprising: performing an electromagnetic field analysis in the time domain of the analysis model using each grid to which information is added by the discretization means.